This invention refers to a system to perform an internal inspection of storage tanks containing liquid fuels. The function of said system is to inspect the inside of the tank through capturing images in real time and to collect selected samples of the stored material and other foreign materials to be analyzed. Said functions are remotely controlled by an operator located nearby and outside of the tank to be inspected.
Storage of liquid fuel in tanks occurs at various stages in the logistical chain of production, distribution, and marketing. Said products are stored in tanks installed in refineries, in terminals, in distribution bases, in large consumer warehouses, and in service and gas stations.
In each of these locations a different type of tank geometry and storage period is used. During this storage period, the product may be contaminated with other types of products or water itself coming from humidity in the air inside the tank, from rainwater entering the tank, from improper handling, from accidental contamination, or from the production process itself.
In an effort to preserve the characteristics of the stored products, to avoid damages and possible contamination to the environment, it is advisable to adopt a cleaning and inspection routine of the tanks where these liquid products are stored. Usually, inspections are very arduous, since they involve emptying the tank completely before the service can be performed, which can result in high direct and indirect costs. In addition to the characteristics of the product, the inspection of the internal parts of the storage tanks allows verification of its walls regarding the appearance of possible points of corrosion and/or deterioration of the inner lining, when applicable.
Currently, it is not possible to precisely know when certain tanks need to be submitted to a cleaning procedure without emptying it. Said lack of precision, however, may cause a loss of time and money since, with this method, many storage tanks are subject to being emptied in order to inspect the inner parts, at a time that may be too soon, even if it is in good condition, which causes unnecessary costs, or too late, which compromises the quality of the stored fuel and the integrity of the tank itself.
The determination of the precise moment at which it is necessary to perform a cleaning of the storage tank allows a significant reduction in the cost of operation in a storage system, which avoids the expense of unnecessary down time and also allows for identifying the presence of contamination in the storage tanks, which may cause product and materials degradation. This problem may be solved by using an inspection system by capturing images in real time from the inside of the tank, as well as collecting samples to be analyzed for any foreign materials that might be inside the tank. Such a system must permit precise positioning of the inspection devices and collecting samples inside the storage tanks. It must also be flexible enough for movement inside the entire tank, independent from the volume of the stored product inside of the storage tank, and be capable of being remotely operated.
Related Technique
At this moment, no system capable of permitting an inspection from any position within the storage tank and simultaneously collecting samples of the stored contents is known. Currently it is only possible to collect samples of liquid fuel and foreign materials by draining and sampling and that are not capable of acting on the entire contents in the tanks, or that reduce the possibility to detect localized problems.
European patent EP 1 156 304 A1 describes a visual inspection system of tanks which includes a viewing unit, a lighting device, a device to capture images and a remote viewing device. The viewing unit is found on the end of one of the inspection system arms. Inside said viewing unit are introduced: a lighting device and the image capturing device. Said image capturing device is connected to the remote viewing device by the operator, which controls the inspection of the tank.
The system described by patent EP 1 156 304 A1 presents two great disadvantages. The first refers to the fact that the viewing device needs to be rigid and not modular, which limits its use in large sized or irregular shaped tanks, since areas that are distant from the observation device are hard to see. The other disadvantage refers to the fact that there is no system for sample collection, which is fundamental for determining the proper time to perform maintenance on the storage tanks.